docs: def id_to_did(did_id, method='op'):
      """Return an Ocean DID from given a hex id."""
      if isinstance(did_id, bytes):
          did_id = Web3.toHex(did_id)
  
      # remove leading '0x' of a hex string
      if isinstance(did_id, str):
          did_id = remove_0x_prefix(did_id)
      else:
          raise TypeError("did id must be a hex string or bytes")
  
      # test for zero address
      if Web3.toBytes(hexstr=did_id) == b'':
          did_id = '0'
      return f'did:{method}:{did_id}'